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Work on diverging diamond at McCaslin/U.S. 36 could begin as early as next month

Construction on unique interchange design could go on for nearly 2 years

By John Aguilar, Camera Staff Writer

Posted:
01/27/2014 09:26:17 PM MST

Updated:
01/27/2014 09:27:29 PM MST

An illustration of the planned diverging diamond interchange at U.S. 36 and McCaslin Boulevard. (Courtesy Town of Superior)

If you like the way traffic flows on the McCaslin Boulevard bridge over U.S. 36, you might want to make a few extra trips over it in the next month or so.

Late next month, the major thoroughfare linking Superior to Louisville will begin a dramatic metamorphosis, transforming from a mundane highway crossing to the first diverging diamond interchange on the Front Range.

"If you have any sentiments now for the bridge, you might want to get them out," said Superior Public Works Director Alex Ariniello, who gave the town's elected leaders an update on the project's timeline Monday evening. "When we're done, we'll have the most innovative diverging diamond interchange in the country."

The novel highway design, which weaves traffic onto the wrong side of the road through a crossing in order to eliminate time-sucking obstructed left turns, has been implemented in just a handful of states since the first was built in Missouri in 2009. Traffic engineers have called diverging diamonds safer and more efficient than traditional interchanges.

Colorado's first diverging diamond was scheduled to open in Grand Junction in December, but has been delayed until March.

The reconfigured interchange at McCaslin Boulevard and U.S. 36 will feature dedicated transit ramps to allow buses to avoid traffic signals, free-flowing bike lanes to keep cyclists from tangling with motorists, and a pedestrian walkway that will afford more protection for those negotiating the interchange by foot.

"Pedestrians using the 12-foot center walkway on the bridge will be protected from the traffic by jersey barriers and the bike lanes," Ariniello said.

But until the $12.5 million project is complete, sometime in late 2015, it will be a tough slog on the bridge —- with disappearing lanes and sidewalks and entries to the turnpike made more difficult.

Two phases of construction

The first phase of construction, lasting from February through June, will include removal of the median on McCaslin, the closure of Superior Plaza Way so a retaining wall can be built, and the shifting of traffic to the west side of the bridge while the east side gets attention first.

The second phase, running from June through August, will be even more disruptive. The loop that takes southbound traffic east to Denver will close and two consecutive left turns will be put in place on the bridge to facilitate traffic flow while construction is ongoing.

Foot traffic on the bridge will end this summer and all pedestrians will be detoured to the Regional Transportation District pedestrian bridge a few hundred feet to the west.

Several trustees voiced concerns Monday about the effect nearly two years of continuous construction might have on residents, commuters and businesses.

Trustee Sandy Pennington wanted to know if businesses near the interchange had been informed about the upcoming roadwork so they could plan for it.

"Are we reaching out to our retailers to make sure they're aware of this?" she asked.

Ariniello said the town already has had a meeting with shopkeepers and store managers about the interchange project.

Holiday concerns

Mayor Andrew Muckle looked down the road to the next big holiday shopping season and wondered how the retailers in the area might be affected by ongoing work.

"Is there a way to minimize the impact to the shopping centers during the holidays at the Superior Marketplace?" he asked.

Colorado Department of Transportation Project Manager Mark Gosselin, who was not at Monday's meeting but gave an interview to the Camera earlier in the day, said the work will be scheduled so as to cause the least amount of hassle for motorists and businesses.

"There will definitely be some short-term closures," Gosselin said. "We'll run these by (Louisville and Superior) and make sure we're picking the right time and keeping the disruptions to a minimum."

The McCaslin interchange is being revamped as part of the second phase of the $425 million U.S. 36 Managed Lanes project, which will add a toll/transit lane in each direction of the busy highway corridor.

The diverging diamond interchange is expected to open for business in the fall of 2015, while the overall managed lanes project will wrap up at the beginning of 2016.

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